The present disclosure relates to a vibrator.
A vibrator, a component converting electric energy into mechanical vibration using a principle of generating electromagnetic force, is mounted in mobile phones to be used for silently notifying a user of call reception by transferring vibration to the user.
Meanwhile, in accordance with the rapid growth of mobile phone market and the trend toward addition of multiple functions to the mobile phone, mobile phone components have been required to have a small size and high quality. In this situation, demand has increased for development of a vibrator having a new structure capable of overcoming disadvantages of an existing vibrator and significantly improving quality.
In addition, as the release of smart phones among mobile phones has rapidly increased, a touch screen scheme has been adopted, such that the vibrator has been used in order to generate vibration at the time of touching a touch screen.
Performances particularly required in the vibration generated at the time of touching the touch screen are as follows. First, since the number of vibration generation at the time of touching the touch screen is larger than that of vibration generation at the time of call reception, an operation lifespan should increase. Second, in order to increase user satisfaction when a user feels the vibration at the time of touching the touch screen, a response speed of the vibration should increase in accordance with a touch speed of the touch screen.
In addition, a piezo haptic actuator has been used as a product capable of implementing these performances. The piezo haptic actuator uses the principle of inverse piezoelectric effect from which displacement is generated when a voltage is applied to a piezo-element, that is, a principle of allowing a weight of a mover to be moved by the generated displacement to generate a vibration force.
A vibrator having the above-mentioned structure has the following features. A bandwidth of a frequency capable of obtaining a vibration force at or above a predetermined level is wide, such that stable vibration characteristics may be implemented, and vibration having low and high frequencies rather than a single frequency in a predetermined frequency range may be variously used. In addition, since the vibrator may implement rapid operation response characteristics, it may be appropriate for implementing haptic vibration of a mobile device such as a mobile phone, or the like.
Meanwhile, the piezo-element generally has a hexahedral shape in which a length thereof is larger than a width thereof. In this case, since the length of the piezo-element should be long in order to secure displacement and vibration, an entire length of the vibrator increases and the piezo-element becomes vulnerable to drop impact.
In order to prevent damage to the piezo-element, a plurality of damper members has been installed in the mover and a housing.
However, in this case, vibration force generated by the mover decreases and a resonance frequency increases.
Further, an internal space becomes narrower due to the damper members, such that it is difficult to secure sufficient vibration force.